Fortical Side Effects

Generic Name: calcitonin

Note: This page contains information about the side effects of calcitonin. Some of the dosage forms included on this document may not apply to the brand name Fortical.

Not all side effects for Fortical may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to calcitonin: injection injectable, injection solution

Other dosage forms:

In addition to its needed effects, some unwanted effects may be caused by calcitonin (the active ingredient contained in Fortical). In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking calcitonin:

Incidence not known
  • Blurred vision
  • chills or fever
  • cough
  • difficulty with breathing
  • difficulty with swallowing
  • dizziness
  • frequent urination
  • headache
  • joint pain
  • muscle aches and pains
  • muscle cramps in the hands, arms, feet, legs, or face
  • nausea or vomiting
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • seizures
  • skin rash or itching
  • slow or fast heartbeat
  • sweating
  • swelling of the hands, ankles, feet, or lower legs
  • tightness in the chest
  • tingling of the hands or feet
  • trembling or shaking of the legs, arms, hands or feet
  • trouble sleeping
  • unusual tiredness or weakness
  • unusual weight gain or loss

Some of the side effects that can occur with calcitonin may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Red streaks on the skin
  • swelling, tenderness, or pain at the injection site
Less common
  • Feeling of warmth
  • redness of the face, neck, arms, and occasionally, upper chest
Incidence not known
  • Abdominal or stomach pain
  • changes in vision
  • diarrhea
  • pain in the eyes
  • poor appetite
  • waking to urinate at night

For Healthcare Professionals

Applies to calcitonin: injectable solution, nasal spray


Side effects are often mild, but commonly occur in about 10% of patients and may occur in up to 30%. About one third of treated patients discontinue the drug due to side effects. Diminished adverse effects occur with the subcutaneous route versus the intramuscular route. After injection, side effects generally occur within an hour.

Calcitonin (the active ingredient contained in Fortical) is a large, manufactured peptide. A certain percentage of what is produced during manufacturing may be "error peptides" which may increase or change the side effects.


Nausea is the most common symptom and occurs in about 10% to 21% of patients. Vomiting, diarrhea, anorexia, and abdominal discomfort are also common effects of calcitonin (the active ingredient contained in Fortical) A metallic taste is reported.

A 71-year-old with Paget's disease was treated with 100 intl units of synthetic salmon calcitonin five times a week. After each injection she experienced nausea, vomiting, and severe shivering. Administration of the 5HT antagonist pizotifen eliminated the side effects.


Cardiovascular side effects including tingling of the hands and flushing of the palms, soles, face, or ears are common. A feeling of pressure in the chest may occur.

Nervous system

Central nervous system side effects of shivering, chills, paresthesias, dizziness, headache, vertigo, migraine, neuralgia, agitation and tremor have been reported. Tetany has been reported rarely.

Within 90 minutes of a subcutaneous injection of 100 intl units of synthetic salmon calcitonin, a 35-year-old woman developed widespread fine tremor which lasted an hour. The reaction could be repeated with a different batch of the drug but not with placebo.


Local side effects including pain, wheals, and erythema at the injection site have been reported. Local reactions are less likely after injection of synthetic human calcitonin (the active ingredient contained in Fortical) than with the synthetic salmon preparation.


Respiratory side effects of shortness of breath and nasal congestion occur infrequently. Rhinorrhea, mild nose bleeds, and nasal dryness may occur with nasal administration.


Antibodies may develop to extracted or synthetic calcitonin (the active ingredient contained in Fortical) products after chronic use. The time to antibody development is variable and patient dependent. Antibodies have been reported with the salmon preparation, and rarely to the human product. Antibody development will render a patient resistant to therapy.


A study of 20 postmenopausal women on calcitonin (the active ingredient contained in Fortical) for osteoporosis for 6 months showed that about seven hours after administration of 100 intl units (intramuscularly) of synthetic salmon calcitonin a mild metabolic acidosis developed.

Hyperglycemia has been reported as a metabolic side effect in patients with Paget's disease. Impaired glucose tolerance may occur in healthy volunteers. Diabetics may lose control of blood sugar.

Metabolic acidosis and hypocalcemia may occur. Transient increases in water and sodium excretion may occur.


Renal side effects including polyuria and urinary frequency may occur in 5% to 10% of patients. Abnormal urinary sediment (but not proteinuria or reduced creatinine clearance) is a rare side effect.


Dermatologic side effects including various rashes, urticaria, and flushing and itching of the palmar and plantar surfaces have been reported. Flushing is a common effect. A single case of disseminated granuloma annulare was temporarily related to synthetic salmon calcitonin (the active ingredient contained in Fortical) use. It is a rare effect.

A 66-year-old woman received a total of 5600 intl units of intranasal synthetic salmon calcitonin for treatment of osteoporosis. Within one month she developed disseminated granuloma annulare (DGA). The calcitonin was continued for one month after symptoms of DGA were recognized. Lesions did not disappear immediately but continued for 10 months. The relationship was temporal but could not be proved as causal.


A 58-year-old woman being treated for osteoporosis with 100 intl units of salmon calcitonin (the active ingredient contained in Fortical) spray per nostril per day developed a progressive bilateral deformation of the alar nasal cartilages. Two depresses, symmetric areas appeared after 4 months. There was nasal septum deformation. The relationship was temporal but could not be proven as causal.

Musculoskeletal side effects including a bilateral deformation of the alar nasal cartilages have been rarely reported after intranasal use. Musculoskeletal weakness may occur.


Hypersensitivity side effects have included a few cases of serious allergic-type reactions (e.g., bronchospasm, swelling of the tongue or throat, anaphylactic shock), including very rare reports of death attributed to anaphylaxis.

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